There are many instances when it is desirable to insert an implantable device into a body cavity such as the urinary bladder or a digestive tract disorder. Such disorders include infections, tumors, or dysfunction. In the case of the urinary bladder, urinary incontinence is also a serious problem. In the following paragraphs these disorders are considered in reference to the urinary tract.
Urinary Incontinence
Urinary incontinence mostly affects women (approximately 10 million in the U.S.A. alone) primarily after childbirth or due to old age. In men, urinary incontinence often occurs as a complication of surgery or old age (approximately 3 million in the U.S.A.).
Incontinence has serious economic, health, social and psychological consequences. Its estimated cost to the health system in the United States in 1993 was US $16 billion. It leads to chronic and severe skin irritation in the genital area, an increase in urinary infections and urosepsis. Fear of incontinence and odors in public cause incontinent people to severely restrict their social activities. The impact on the mental health of the affected people may be even more devastating than the social and health consequences. They suffer severe embarrassment, loss of self-esteem, depression and anxiety.
Urinary incontinence can be divided into 4 groups:    Stress Incontinence—is the involuntary release of urine due to a sudden increase in the intraabdominal pressure caused by laughing, sneezing, coughing, running, etc. This is the most common type of incontinence and in women may be the result of childbirth, estrogen deficiency, unsuccessful surgical repairs for incontinence or pelvic irradiation. In men, it often happens after surgery for benign enlargement of the prostate gland or after radical removal of the prostate.    Total Incontinence—is the continuous leak of urine entering the bladder due to failure of the sphincteric muscles.    Urge Incontinence—is involuntary loss of urine due to involuntary bladder contractions. This type of incontinence mostly affects the elderly who leak until they reach a toilet.    Mixed Incontinence—is a combination of stress and urge incontinence. This condition is more common in elderly women than men.
Ideally, treatment of incontinence should provide permanent dryness and is easy to perform.
Pharmacological treatments of bladder dysfunctions are based either on estrogen replacement for treating post-menopausal vaginal and urethral atrophy or on agents affecting the tonus of the bladder muscle. Since affected elderly women suffer from both hormonal deficiency and urge incontinence, both types of agents are usually prescribed simultaneously.
Surgical treatments are based on restoring the anatomical changes causing the incontinence. Although in the short-term most surgical procedures restore continence, the long-term prognosis is usually unsatisfactory. Moreover, surgery entails morbidity and high expenses.
Conservative/behavioral treatments are based on pelvic floor muscle exercises, bladder training, biofeedback, vaginal cones, low-frequency electrostimulation of pelvic floor muscles, intravaginal bladder neck support pessaries, urethral meatus suction cups and intraurethral devices. Conservative treatments are time consuming and require the patients' understanding, cooperation and persistence.
Devices which have been used to obtain almost immediate dryness in incontinent people can be divided into two groups:
(1) Urethral Plugs/Inserts
These comprise a flexible rod having a 14 Ch. (approximately 4.5 mm) diameter and a length adjusted to fit the length of the patient's urethra. The rod has an inflatable balloon on its bladder end and a flange at other end. After insertion of the device, the balloon is inflated in the bladder. The balloon and the flange maintain the device in its proper position within the urethra. The balloon and rod form a mechanical barrier to retain the urine within the bladder. The balloon must be deflated and the device removed and discarded prior to voiding. Such inserts are known in the art, for example, the device known as RELIANCE™ produced by UroMed Corp., U.S.A.
Since inserts are discarded after each voiding and replaced with a new one by the patient, manual dexterity of the patient is required. Insertion of an insert into a female has the risk of pushing vaginal and perineal bacteria into the bladder and insertion of an insert a few times a day increases this risk. The inconvenience of removing and inserting a new device and its costs, in addition to the infection risk, are the major disadvantages of these devices.
(2) Valve Catheters
These comprise a tube with a valve at one end. The bladder end of the device typically has a balloon or flanges for retaining the device in place and a flange at the other end to prevent migration into the bladder. The valve is opened for voiding through the lumen of the catheter with the help of an external magnet. The tube typically has a 18 Ch. (6 mm.) to 20 Ch. (approximately 7 mm) diameter and a length adjusted to fit the patient's urethra. For male incontinence, an active intraurethral Foley-type catheter is used. This device has a retaining balloon at its bladder end and another smaller balloon under the prostate for fixing the device in place. The magnet activated valve is situated at the end of the device near the distal end of the urethra. Active inserts are typically left indwelling up to 4 weeks and are then replaced. Examples of such catheters are disclosed in U.S. Pat. Nos. 5,030,199 and 5,234,409.
Valve catheters are more convenient for the patient than the inserts. However, in females they cause ascending infection because they connect the bladder with the vulva which is rich in pathogenic bacteria, expecially Escherichia Coli. Even with continuous use of antibiotics, infection is unpreventable in the majority of cases.
During prolonged use of catheters or inserts in female patients, a relaxation of the urethra occurs and the patients may start to leak around the device. Unfortunately valve catheters and inserts are unavailable in increasing diameters.
A significant disadvantage of both the inserts and the valve catheters is the discomfort felt by the patient especially when sitting and during sexual intercourse (felt by the patient and the partner). The present invention therefore provides a device for the treatment of urinary incontinence in which the disadvantages of the prior art devices are substantially reduced or eliminated.
Urinary Tract Infections
Nearly half of all women experience urinary tract infection (UTI) at some point in their lifetime aid most of these infections are confined to the bladder. Isolated UTIs can be treated by short and effective antibiotic treatment. However, recurrent UTIs often occur ill women due to antibiotic resistant bacteria. In this case complicated infections often exhibit multidrug resistance and necessitate longer antimicrobial drug administrations.
Treatment of UTI often requires urinary levels of antimicrobial drugs that are several hundred times greater than those allowable in the blood. Many antibacterials cannot be used in UTI because, when taken orally or intravenously, they do not attain the required concentration in the urine, without exceeding the allowable limit in the blood. It would therefore be desirable to be able to continuously introduce antimicrobial drugs continuously and directly into the bladder.
Bladder Tumors
Even after resection, bladder tumors may not only recur but may also invade deeper in the bladder wall. Due to the heterogenity of these tumors (from low-grade tumors showing a benign course to highly malignant high-grade tumors), there does not exist a single approach to the surveillance and treatment of these tumors. Intravesical drug therapies are often used for reducing tumor recurrence. In this approach, an immunotherapeutic or chemotherapeutic agent is inserted into the bladder through a catheter. This treatment is typically repeated once a week for 6 weeks and then once a month for a period of 6-1.2 months. However, periodic treatment has not been established as being effective in altering the progression of the tumor. Continuous local treatment with chemotherapeutic or radioactive materials may treat or prevent not only superficial tumors but also deep tumors as well. It would therefore be desirable to be able to introduce antitumoral drugs continuously and directly into the bladder.
Bladder Dysfunction
During filling, the bladder muscle relaxes for keeping the intravesical pressure low while it contracts for voiding. Certain diseases such as spinal cord injuries, diabetes, multiple sclerosis, or hormonal changes after menopause or old age in both sexes may cause a hypo contractility or, paradoxically, hyper contractility of the muscle. In atonic bladder, pharmacological treatment is not very effective. In hyperreflexic bladder, drugs for relaxing the bladder cause constipation and mouth dryness and are therefore not tolerated well by the patients.
Diagnosis of bladder dysfunction requires continuously monitoring various bladder parameters during filling and/or voiding. These measurements usually are made by inserting a catheter connected to a measuring device into the bladder. This is done, for example, in uroflowmetry (measurement of urinary flow rate) which is non-invasive, simple and inexpensive. However, its sensitivity and specificity are low. Cystometry is an invasive technique for measuring bladder capacity, compliance and muscle tonus. Pressure-flow study is an invasive and costly test for distinguishing patients with low urinary flow due to obstruction or bladder antonia, from those with high intravesical pressure and high urinary flow. It is therefore a need in the art for a simple and inexpensive technique for intravesicular monitoring.
In the diagnostic procedure known as “urodynamics”, the bladder is filled through a catheter, and the response of the bladder is monitored. Available 24 hour urodynamic monitors have catheters or wires passing through the urethra, connecting sensors inserted into the bladder to a recorder. The connecting wires and catheters inadvertently introduce pathogenic bacteria from the genital areas into the bladder. It is therefore desirable to be able to monitor bladder function over several cycles of filling and voiding without the need for such wires or catheters.
Diagnosis of some intravesical pathological conditions often involves inserting an endoscope into the bladder and optically scanning the bladder walls. In cases of bleeding in the ureters or the kidneys, the observation of blood coming through the ureteral orifices allows determination of the origin of the bleeding. However, if the bleeding has temporarily stopped at the time of the examination, or if the blood concentration in the urine is insufficient to make the urine red or pink, endoscopy is of little value in reaching a diagnosis. In such cases more invasive procedures are performed in order to enter the upper urinary tract. It is therefore desirable to be able to monitor the bladder over long periods of time.
Bladder shape during filling and its contraction during voiding is important for the diagnosis of certain bladder pathologies. These functions can be followed in fluoroscopy and by sonography. These techniques however are not accurate and cannot be used for monitoring changes in bladder shape over long periods of time. It would therefore be desirable to be able to continuously image the bladder interior over long periods of time.
U.S. Pat. No. 6,293,923 to Yachia et al., discloses a balloon for insertion in the urinary bladder for treatment in order to treat or monitor the bladder. U.S. Pat. No. 4,925,446 discloses a balloon for insertion into the stomach.